The field of prosthetics has seen many advances to enhance quality of life by improving mobility and returning functionality to persons suffering from injured or missing limbs. Prostheses attempt to mimic the movements of the limb that they replace. For example, a healthy functioning ankle will go through a series of plantarflexion and dorsiflexion motions during gait without the person having to consciously control the ankle movement. Therefore, improvements have been sought to produce prosthetic ankle joints that may mimic the movements of a healthy ankle to improve the patient's comfort and functionality.
A prosthetic ankle joint must exhibit sufficient dorsiflexion and plantarflexion dampening when the patient walks to permit the most natural gait possible. On the other hand, when the prosthesis user is standing, sufficient stability and support must be achieved to permit a stable stance. It is therefore necessary that the prosthesis is operated in two different states, i.e., for walking on the one hand and for standing on the other hand. To build the prosthesis light-weight, with little susceptibility to faults, low costs and energy savings, the prosthesis should be able to do without electronic control elements. Different prosthetic ankle joints are known having two separate cylinders interconnected via a fluid passage. During movement of the ankle, fluid is guided from one cylinder into the other cylinder. The fluid resistance in this fluid passage is responsible for a dampening of the joint. However this type of ankle joint requires significant space, making it difficult, if not impossible, to arrange this kind of ankle joint in a decorative foot cover.